Marcomannic Wars

The Marcomannic Wars were a series of wars fought by the Roman emperor Marcus Aurelius against the Germanic Marcomanni and Quadi and the Sarmatian Iazyges along the whole length of the Danube River frontier of the Roman Empire from 166 to 180 AD. The Romans succeeded in repelling the barbarian invasion of the Roman Empire and forcing the tribes to accept terms favorable to them, but their plants to annex Sarmatia (the Hungarian plain) and Marcomannia (Moravia, Slovakia, and northern Bavaria) were abandoned, and the territorial boundaries remained the same.

Background
During the mid-2nd century, the Roman Empire was weakened by the outbreak of the Antonine Plague (brought back to the empire by sick soldiers returning from Antoninus Pius' war with Parthia from 161 to 166), which killed 5 million people, as well as the southeastern migration of the Goths from the Vistula River, putting pressure on the other Germanic tribes. The Germans and other nomadic peoples such as the Sarmatians launched raids south and west across Rome's northern border, particularly into Gaul and across the Danube. From 162 to 165, the Chatti and Chauci invaded Raetia and Germania Superior, but their invasion was repulsed. The Roman emperor Marcus Aurelius then embarked on a campaign of over ten years against the Germanic tribes with the goal of securing Rome's borders and possibly conquering Pannonia and the Germanic tribes' lands in Moravia, Slovakia, and Bavaria.

Wars
In 167 AD, a force of 6,000 Lombards invaded Pannonia, and, while they were defeated with relative ease, they marked the beginning of what was to come. The Roman governor of Pannonia, Marcus Iallius Bassus, initiated negotiations with 11 tribes, with the Roman client king Ballomar of the Marcomanni serving as a mediator. The barbarians temporarily left Roman lands, but no permanent agreement was reached. That same year, the Vandals and Iazyges invaded Dacia, killing its governor Calpurnius Proculus. To counter them, the veteran Legio V Macedonica was moved from Moesia to Dacia, closer to the enemy.

In 168 AD, Marcus Aurelius ordered a punitive expedition into Pannonia, and he and his co-emperor Lucius Verus raised Legio II Italica and Legio III Italica before crossing the Alps. The approach of the imperial army to Carnuntum persuaded them to withdraw and offer assurances of good conduct. Lucius Verus died in 169 AD, and, after attending his funeral, Marcus Aurelius returned north with his son-in-law Claudius Pompeianus, intending to subdue the independent tribes such as the Iazyges. The Iazyges killed the Roman governor of Moesia, Marcus Claudius Fronto, and several other tribes invaded Roman territory as the Romans were entangled in the struggle with the Iazyges. To the east, the Costoboci crossed the Danube, ravaged Thrace, and destroyed the Eleusis Telesterion near Athens. In the west, the Marcomanni defeated 20,000 Roman soldiers at the Battle of Carnuntum, and Ballomar led the main portion of his host towards Italy, while another force ravaged Noricum. The Marcomanni razed Opitergium (Oderzo) and besieged Aquileia, the first time that hostile forces entered Italy since the Cimbri invasion of 101 BC. Marcus Aurelius responded by redeploying several Roman frontier forces against Ballomar, and Pompeianus and his lieutenant Pertinax relieved Aquileia in 170 AD and evicted the invaders from Roman territory by the end of 171 AD. The Romans made peace with the Quadi and Iazyges, while some tribes of Vandals became Roman allies.

In 172 AD, the Romans crossed the Danube into Marcomanni territory. The Romans subdued the Marcomanni, and Marcus Aurelius adopted the nickname "Germanicus" because of his victory. In 173 AD, after the Quadi broke their treaty with the Romans, and a miracle was said to have occurred: a rainstorm allowed for the thirsty and overheated Romans to be refreshed, while lightning struck the Quadi. Reports varied as to the cause of the miracle, with some claiming that an Egyptian magician prayed to Hermes, and others claiming that it was the result of a Christian prayer. That same year, Didius Julianus repelled a Chatti invasion on the Rhine frontier as the Chauci raided Belgium. In 174 AD, the Romans marched against the Quadi after they deposed their pro-Roman king Furtius and installed his rival Ariogaesus in his place. Marcus Aurelius deposed Ariogaesus and had him exiled to Alexandria, and the Quadi were subjugated by the year's end. In 175, the Romans signed a treaty with the Iazyges, and King Zanticus delivered 100,000 Roman prisoners and provided 8,000 auxiliary cavalrymen; Marcus Aurelius also received the victory title "Sarmaticus". He intended to establish two new Roman provinces in the lands of the Marcomanni and Quadi, but he was distracted by Avidius Cassius' eastern rebellion.

In 177 AD,